ta·chis·to·scope (tă-kĭstə-skōp′, tə-)
An apparatus that projects a series of images onto a screen at rapid speed to test visual perception, memory, and learning.
[Greek takhistos, superlative of takhus, swift + -SCOPE.]
ta·chis′to·scopic (-skŏpĭk) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.